I believe it varies, depending on design. Some of the fluff describes the bolters the Space Marines carry as being very, very large, whereas the ones the Sisters of Battle carry are somewhat smaller.

I would suppose that your average bolter, given the dimensions of its ammunition, would be pretty large affairs. Figure about twice the bulk of your average assault rifle, maybe more, and probably two to three times as heavy.

Expanding on Wyddr's answer, though, take one of these, and keep the length but multiply the other dimensions by two, mostly to accommodate its 0.75 caliber ammunition. Wyddr's mass estimate seems logical as well.

For Space Marine weaponry, add a third to all those "final" dimensions and mass, just as a general guideline.

Wyddr touches on this, but it is important to note that there are (at least) two classes of bolt weaponry - those carried by the Space Marines, and those carried by everybody else. Obviously those carried by Space Marines are bigger, and in proportion with their enhanced bodies, and those used by SOB or guard are smaller, with smaller shells to match.

the bolter uses .998 rounds according to DOW2. the .998 round is about the length of a uk size 9 foot so thats pretty huge. also the weapons size being proportional to current weapons would make it approximately 8ft long X 10" wide X 2ft high.

« Last Edit: June 30, 2009, 08:37:11 PM by smithmyster666 »

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The problem I see is that I don't necessarily see the Bolter as an assault rifle, more like a quick-firing grenade launcher. a .75 round is really rather large, just under 20mm for metrics (like me), and the bolter round is an explosive thing. So I see Bolters less as assault rifles, more as scaled-down grenade launchers.

A big thing is the size of the round. Taking the .75 calibre (because I see that as more realistic), we have a round that (taking the garden variety 40mm grenades of today as a base) is 20mm diameter, and about 50mm high. That's a big, squat round, however you look at this, and the size of the magazine supports this somewhat. It's just not big enough to take a conventional rifle round (Very long vs small diameter). The barrel is also very short, suggesting a weapon that is not designed for accuracy, but just to 'point it in the right direction'. I remember reading somewhere that the Godwyn pattern bolter is smoothbore, but I can't be certain, but if it is, it reinforces the issue of the bolter really being a small grenade launcher.

Now, looking at the size, this all makes things a lot easier to understand. We can make a good estimate at the magazine size. The sickle magazine is meant to take 20-30 rounds. Now, stacked alternately like in modern firearms, and using the smaller number, this gives us a rough height of about 35cm, depending on how acute the stack is, and a width of about 5cm. That's big, and I'd say, roughly consistent with the size of the magazine on the models. a 30-round magazine has us sitting at about 50cm long magazine, which is just far too big, in my head.

Now, onto the internal mechanisms of the Bolter. If it uses a standard percussion cap firing system like modern firearms, we need somewhere for a firing pin and spring assembly. Then we need a holder for the shell, springs to push it into the breach and then pull back the empty case after firing. That's large, and I'm guessing takes up most of the rear mass of the bolter, considering the size of round and firing stresses. If it's electrically fired, we need a lot less working parts, and the size of the working parts will be reduced, so that they take up less space inside the weapon. Then we need all the gubbins included, like genetic grips and targeting systems, taking up yet more space inside the thing, almost too much space in my head, but GW don't do 'tru-scale' that coincides with the fluff, so that's understandable.

All in all, for the bolter, as a rough guess I'd say you're looking at a barrel length of about 45-55cm (working this out in my head), a body width of about 7-10cm and a height dependent on the magazine, but empty, I'd hazard a guess at 35cm high. Sounds very squat and fat for an assault rifle, but sounds about right for a 20mm high-velocity grenade launcher.

BUT, on the other hand, you could take all of what I've said and throw it out, because I don't live 38,000 years in the future and I don't know what kind of tech they have!

Personaly, i think a percussion cap firing system is a little simplistic for one of the holy weapons in the Imperium. I've always imagined them working on something more like the electrical trigger of the Metal-Storm prototype weapons, but with a working loading mechanism. This alone would free up a good deal of space in the actual body of the weapon. As for the actual size... I don't have one on hand, but when i get home I'll measure the size of the model, and compare it proportionally to the standard 8-Foot Space Marine.

Again, GW doesn't really scale things right, but it may give us a bit of insight.

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Personaly, i think a percussion cap firing system is a little simplistic for one of the holy weapons in the Imperium. I've always imagined them working on something more like the electrical trigger of the Metal-Storm prototype weapons, but with a working loading mechanism. This alone would free up a good deal of space in the actual body of the weapon. As for the actual size... I don't have one on hand, but when i get home I'll measure the size of the model, and compare it proportionally to the standard 8-Foot Space Marine.

Again, GW doesn't really scale things right, but it may give us a bit of insight.

This.

Also, if I recall correctly, Bolt rounds are Caseless ammunition, which, from my understanding, doesn't work with traditional "Hammer Action" firearms, depending on the propellant. The are, essentially these, excepting that they're actually effective. The Bolts are, essentially, miniature rockets, all the gun does is sest it's engire going/propel the bolt till the engines engage.

Notwithstanding the cased/caseless debate, everyone agrees that bolt shells are in effect miniature rockets. To that end, it would make sense if bolters are smoothbore (since the shells would stabilize themselves, by spinning or with fins, whatever). Also, then accuracy would not be affected by barrel length, which also explains why in old art or models you see bolters with the clips practically at the end of the barrel.

the bolter uses .998 rounds according to DOW2. the .998 round is about the length of a uk size 9 foot so thats pretty huge. also the weapons size being proportional to current weapons would make it approximately 8ft long X 10" wide X 2ft high.

I've just checked this myself -- you are getting mixed up with the date of issue. It is well documented in multiple fluff sources that a bolter fires .75 calibre shells.

Personaly, i think a percussion cap firing system is a little simplistic for one of the holy weapons in the Imperium. I've always imagined them working on something more like the electrical trigger of the Metal-Storm prototype weapons, but with a working loading mechanism. This alone would free up a good deal of space in the actual body of the weapon. As for the actual size... I don't have one on hand, but when i get home I'll measure the size of the model, and compare it proportionally to the standard 8-Foot Space Marine.

Again, GW doesn't really scale things right, but it may give us a bit of insight.

This.

Also, if I recall correctly, Bolt rounds are Caseless ammunition, which, from my understanding, doesn't work with traditional "Hammer Action" firearms, depending on the propellant. The are, essentially these, excepting that they're actually effective. The Bolts are, essentially, miniature rockets, all the gun does is sest it's engire going/propel the bolt till the engines engage.

Actually, they've got cases, otherwise they wouldn't have case ejection ports on the side. I agree with the rest.

I don't have one on hand, but when i get home I'll measure the size of the model, and compare it proportionally to the standard 8-Foot Space Marine.

Again, GW doesn't really scale things right, but it may give us a bit of insight.

Anyone fortunate enough to have been to the Warhammer World museum in Nottingham UK before the exhibits got scattered all over the world, would have seen the life size Marine and also the storm bolter they had on display. The Marine itself was probably about 7 foot tall, possibly 8. I'm speculating here because obviously I didn't measure it, but the boltgun would have to have been 24" long (the marine having to carry it 2-handed). The storm bolter is a massive weapon (esentially 2bolters together), the average human would have extreme difficulty even lifting it. Guessing again I would have put it at 30" long with musc more mass.

I'm not sure but the Marine Statue outside of GW UK HQ could be 1:1 scale. I don't have an internet picture hosting facility so I can't post a picture of it I have from earlier this year.

On the cased/caseless issue, I support the cased party for a number of reasons. Firstly, as Koval pointed out, there's a whacking great ejection port on the side of the bolter. Don't need that in a caseless weapon. Secondly, in a lot of the fluff images, including the masterfully done painting on the front of the old SMurf 'dex, you can clearly see shells coming out of the Bolters, and that's official cannon.

But then again, if they are electrically fired rounds, we could have a situation where it can deal with both cased and caseless rounds. Might be that some, like the Inferno rounds, for example, are caseless while the standard round is cased.

The way the bolter fires as I see it, is roughly akin to the Javelin Anti-tank missile launcher, in that an electrical ignition fires a small charge, shoving the round down the barrel and separating it from the case, as well as cycling the action etc. When the round leaves the barrel the main rocket motors fire and it shoots off to it's target.Now that I really think about it, an electrical ignition system looks more and more likely.

There isn't a particularly good reason why bolters *wouldn't* use a percussion-cap system, really. It has to be easier to accomplish than electrical ignition, for one thing. It makes the weapon need less maintenence, for another. About the only drawback might be that it would have difficulty firing in a vacuum, but that's probably pretty easily solved by sealing the firing chamber and pumping in just a bit of oxygen (requiring a bit of a refit, but nothing major).

I have always understood the bolt rounds as having two stages, if you will. First off is the conventional casing/explosive that propels the bolt out of the barrel of the gun. This is probably pretty small--just enough to chuck the thing a few yards/meters, after which point the jet on the bolt itself kicks in. This probably would be done to reduce blow-back from the jet's exhaust doing things like needlessly heating up the barrel, igniting other ammunition, or even to make firing in squad formations a bit less complicated (nothing worse than having your shoulder singed off because the guy behind you fired a bolt too close).

I have always understood the bolt rounds as having two stages, if you will. First off is the conventional casing/explosive that propels the bolt out of the barrel of the gun. This is probably pretty small--just enough to chuck the thing a few yards/meters, after which point the jet on the bolt itself kicks in. This probably would be done to reduce blow-back from the jet's exhaust doing things like needlessly heating up the barrel, igniting other ammunition, or even to make firing in squad formations a bit less complicated (nothing worse than having your shoulder singed off because the guy behind you fired a bolt too close).

Yes, I've heard that too. I always figured that was a compromise of sorts. Since the bolter was originally described as being caseless, but later depicted as using "cased" ammunition in gw art and fiction. I don't know if it's official tough. Another compromise could be big imperium = many kinds of bolters.

And I'm sure there are dozens of other, less-well-known variants made for the guard or PDFs as well as for the black market. These just are mass produced and not blessed by techpriests, simply stamped, forged and issued.That raises another issue when talking about size. What pattern bolter are we talking about, for starters? I mean, I know we are talking about the Astartes MK Vb Godwyn pattern, the standard SMurf issue bolter, but we can't assume, for to assume makes and ass out of you and me.

There isn't a particularly good reason why bolters *wouldn't* use a percussion-cap system, really. It has to be easier to accomplish than electrical ignition, for one thing. It makes the weapon need less maintenence, for another. About the only drawback might be that it would have difficulty firing in a vacuum, but that's probably pretty easily solved by sealing the firing chamber and pumping in just a bit of oxygen (requiring a bit of a refit, but nothing major).

Actually, electrical firing system are not only easier to set up, but break down far less often because the only real moving part is the round. They also allow for a considerably greater rate of fire (For instance, the dual barrel Metal-Storm pistol can fire 3 rounds before the weapon actually recoils). Also, due to the fact they are still using hydrocarbon explosives, they are just as affected by low oxygen environments as a standard round.

Still we are talking about the Imperium here. It is possible, and indeed likely, that various Bolter Patterns use different firing systems.

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Notwithstanding the cased/caseless debate, everyone agrees that bolt shells are in effect miniature rockets. To that end, it would make sense if bolters are smoothbore (since the shells would stabilize themselves, by spinning or with fins, whatever). Also, then accuracy would not be affected by barrel length, which also explains why in old art or models you see bolters with the clips practically at the end of the barrel.

You could have saboted shells and use rifling, though, if you wanted. It would get a little ridiculous, perhaps -

I believe that British and French tank guns are rifles, even though the effectiveness of HEAT and APFSDS shells is reduced by rotation. So instead of the whole shell rotating, there's just a sleeve that engages the rifling. The sleeve spins freely around the shell, and it's heavy enough to keep the shell from tumbling. I think the APFSDS rotating collar breaks away as it exits the barrel, but don't quote me on that.

But with all this complexity, the reliability of the bolter - for which it is famed - would surely drop.

So I'm sticking with imagining it as a cased 12-ga or so round, in a straight, non-necked cartridge that has a relatively small charge. Short and stubby cartridges. Like that 20mm grenade launcher from the now-defunct OICW "let's make guns awesome" project.

« Last Edit: July 2, 2009, 09:07:28 PM by Shaviv »

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And a bolter would probably be similar size to the OICW for that reason, maybe a tad larger. Most images seem to show bolters to be about the length of modern assault carbine, just bulkier. Remember that Space Marines are bigger then normal humans, but that aren't that much bigger, they might be more comfortable using an over sized grip and no trigger guard, but otherwise they wouldn't need further modification.

A lot of the pseudoscience fluff and flavor text fluff about bolters don't really match up. A micro rocket launcher would probably have a relatively low recoil (since the round would get lots of it's momentum from the rocket, it would only need the initial charge to be enough to kick it clear of the barrel, the lack of a stock on most patterns of bolter, both for SMs and normal humans, support this) but there are plenty out there that insist that a bolters recoil can dislocate or remove a limb (I guess because they just can handle the idea that something powerful would also be easy to use).